Turbine blade

Abstract

A turbine blade for a turbomachine includes a turbine blade with a leading edge and a trailing edge. The blade includes a radially outer platform with at least one lip extending radially towards the outside. The radially outer end of the leading edge and/or of the trailing edge of the turbine blade airfoil extending axially upstream and/or downstream, respectively, in relation to the platform. The blade has at least one partition extending radially towards the outside from the radially outer end of the turbine blade airfoil and axially between the leading edge and the upstream end of the platform and/or between the trailing edge and the downstream end of the platform.

Claims

1. A turbine blade for a turbomachine configured to extend around an axis of the turbomachine, the blade having a vane extending radially with respect to the axis between a radially inner platform and a radially outer platform, the vane comprising an axially upstream leading edge and an axially downstream trailing edge, the radially outer platform comprising an upstream end and a downstream end, the radially outer platform comprising at least one radially outwardly extending seal lip wherein at least one of the radially outer end of the leading edge of the vane and the trailing edge of the vane extends one of axially (a) upstream relative to the upstream end of the platform and (b) downstream relative to the downstream end of the platform the blade having at least one partition extending radially outward from the radially outer end of the vane, and at least one of (a) axially between the leading edge and the upstream end of the platform and (b) between the trailing edge and the downstream end of the platform.

2. The turbine blade according to claim 1, wherein the partition extends axially between one of (a) the leading edge and an upstream surface of the seal lip respectively and (b) the trailing edge and a downstream surface of the seal lip.

3. The turbine blade according to claim 2, wherein the partition extends radially outwardly to the radially outer end of the seal lip.

4. The turbine blade according to claim 2, wherein the partition extends radially outwardly over only part of a radial dimension of the seal lip.

5. The turbine blade according to claim 1, wherein the partition extends in a direction at an angle to the radial direction.

6. The turbine blade according to claim 1, wherein the partition has at least one of an upstream end and a downstream end edge which is straight and forms an angle with the radial direction, the angle lying in a plane normal to the axial direction.

7. The turbine blade according to claim 1, wherein the seal lip extends in a plane, at least part of the partition extending perpendicularly to the plane of the seal lip.

8. The turbine blade according to claim 1, wherein the seal lip extends in a plane, at least part of the partition extending in a plane forming an angle with the axis of the turbomachine.

9. The turbine blade according to claim 1, wherein the partition is curved.

10. The turbine for a turbomachine, comprising a bladed wheel having turbine blades according to claim 1.

11. The turbine blade according to claim 9, wherein the partition is concave as seen from the lower surface of the vane.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) FIG. 1 is a schematic view of a turbine blade according to the prior art;

(2) FIG. 2 is a schematic view of an example of turbine blade platform according to an embodiment of the invention;

(3) FIGS. 3A to 4B are perspective views illustrating part of a blade in different variants of the invention.

DETAILED DESCRIPTION

(4) Hereunder, the terms “upstream” and “downstream” are defined in relation to the direction of gas flow in the turbomachine, particularly in the secondary flow path. Also, les terms “radial” and “axial” are defined in relation to the axis of the turbine wheel. Each turbine blade extends radially outwards from the turbine wheel disc, whose axis of rotation extends axially.

(5) Reference is made below to FIG. 2 and following in relation to the invention, FIG. 1, concerning the prior art, having already been described above.

(6) FIG. 2 shows a part of a turbine blade 13 for a turbomachine according to the invention. A plurality of turbine blades 13 according to the invention are intended to be mounted on a disc so as to form a turbine wheel.

(7) Blade 13 comprises a radially extending vane 14, and a radially outer platform 15 located at the radially outer end of vane 14. Vane 14 has an axially upstream leading edge 16 and an axially downstream trailing edge (not shown). Platform 15 has an upstream end 17 and a downstream end (not shown). Said platform 15 also has seal lips, namely an upstream seal lip 18 and a downstream seal lip 19 in the example shown in the figures.

(8) In the illustrated example, platform 15 extends axially between the two seal lips 18, 19 and is openworked in relation to platform 5 of the prior art presented above. Platform 15 does not include a section extending axially beyond seal lips 18, 19.

(9) An openwork platform with a part extending beyond the seal lips can also be considered.

(10) In both cases, the radially outer end 20 of the leading edge 16 of vane 14 extends axially upstream from the upstream end 17 of platform 15. Similarly, the radially outer end of the trailing edge (not shown) of vane 14 extends axially downstream relative to the downstream end of platform 15.

(11) The blade 13 according to the invention also has a partition 21. Partition 21 is located radially outside of the radially outer end 20 of the leading edge 16 and/or trailing edge (not shown) of the vane. Indeed, partition 21 extends circumferentially opposite the radially outer end 20 of vane 14.

(12) In addition, partition 21 extends axially between the leading edge 16 and the upstream end 17 of platform 5, and/or respectively between the trailing edge and the downstream end of platform 15.

(13) Partition 21 shown extends axially between the leading edge 16 and an upstream surface 22 of seal lip 18. Similarly, it is conceivable that partition 21 could extend axially between the trailing edge and a downstream surface of the seal lip.

(14) In the embodiment illustrated in FIG. 2, partition 21 extends over only part of the height, i.e. the radial dimension, of the seal lip 18, 19 concerned.

(15) Partition 21 has a straight end edge 23 forming an angle “a” with the radial direction or radial plane. The angle “a” is, for example, between 30° and 90°. The angle “a” lies in a plane normal to the axial direction.

(16) Several embodiment variants are shown in FIGS. 3A to 4B.

(17) The geometric shape and positioning of partitions 21 can vary depending on the application.

(18) In the embodiment variants shown in FIGS. 3A and 4A, the partition 21, 27, extends radially outwards substantially to the radially outer end 24, 26 of seal lip 18, 19. In other words, partition 21, 27 is approximately the same height as seal lip 18, 19.

(19) Preferably, there is a radial operating clearance between the radially outer end 25 of partition 21, 27 and the radially outer end 24, 26 of seal lip 18, 19. This operating clearance is for example between 0.5 and 2 mm.

(20) Such a clearance thus prevents any friction of partition 21, 27 on the abradable material.

(21) In the embodiment variants shown in FIGS. 3B and 4B, partition 21, 27, extends radially outward over only part of the radial dimension of seal lip 18, 19.

(22) In other words, the radially outer end 25 of partition 21, 27 is offset radially inward from the radially outer end 24, 26 of seal lip 18, 19.

(23) The radial distance between the radially outer end 25 of partition 21, 27 and the radially outer end 24, 26 of seal lip 18, 19 is for example between 0.5 mm and 2 mm.

(24) As shown in FIGS. 3A to 4B, partition 21 at upstream seal lip 18 and partition 27 at downstream seal lip 19 may extend in a direction at an angle (3) to the radial direction.

(25) The angle (3) is, for example, between 0° and 60°.

(26) The angle (3) is inscribed in a plane comprising the axial and radial directions.

(27) Note that, in the embodiment variants of FIGS. 3A to 4B, the angle “a” is equal to 0.

(28) In each alternative construction of FIGS. 3A and 3B, the upstream partition 21 is perpendicular to the plane of the upstream seal lip 18.

(29) Furthermore, in each embodiment variant of FIGS. 4A and 4B, the downstream partition 27 extends, at least in part, in a plane forming an angle of 0 with the X axis of the turbomachine. Thus, the partition and seal lip each extend radially from the blade platform. In particular, the downstream partition 27 is inclined in the direction of the blade rotation direction R so as to form a deflector for the air flow.

(30) In other words, downstream partition 27 is inclined towards the lower surface. The inclination towards the lower surface is particularly interesting because it makes it more difficult to recirculate air from the lower surface to the upper surface area.

(31) Said angle 0 is for example between 0° and 60°.

(32) In each of the embodiments described above, partition 21, 27 constitutes an obstacle to air recirculation from the lower to upper surface area and thus reduces the losses associated with such recirculation. This increases turbine performance, while limiting the weight of the blade 14 due to the limited dimensions of the outer platform 15.